Many of the Mangos I’ve grown in my backyard have had seeds like that. I would say 50% of my fruit are like that. I wonder if it has something to do with our climate or certain pathogens that causes incomplete pollinization?
I’ve experienced this with Glenn, Edwards, Venus, Sweet Tart, Maha Chanok, Gary, Pineapple Pleasure, Green Thai mango, NDM and Lemon Zest.
Simon